log2, log2f

[Christopher Faylor]

On Wed, Mar 18, 2009 at 06:07:11AM -0600, Eric Blake wrote:
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>According to Yaakov (Cygwin/X) on 3/17/2009 7:50 PM:
>> SUSv3 requires that log2 and log2f be defined as functions (at least)
>> and may also be defined as macros.  Right now, though, these are only
>> defined as macros, and besides being noncompliant, it also creates false
>> negatives with configure AC_CHECK_FUNC[S] tests.
>> 
>> Here's my first attempt at a patch to define these as functions instead.
>
>Your patch adds the functions (good) but deletes the macros.  SUSv3 (and
>v4) allow these to be macros in addition to functions.  Since the body is
>so trivial, maybe it is worth keeping the macro around to avoid the
>penalty of an extra function call, with minimal impact to code size in the
>common usage of log2?

I discussed this with Yaakov on irc but how would you do this exactly?  Where
would you define the function if log2 is already defined as a macro?

cgf